弱层理面急倾斜层状岩体巷道顶板膨胀浆体注浆加固作用机理研究

To solve the problem that the tunnel roof in steeply inclined layered rock with weak beddings is prone to be damaged along the beddings named "slip along beddings", the expansion constraints stress and mechanical behavior will be studied, with the grouting reinforcement idea named "first squeezing then bonding" which the rocks beside the beddings are squeezed during the process of bonding the beddings. By the means of rock mechanics test, numerical simulation, similar simulation and theoretical analysis, the relationship between expansion constraints stress and normal constrained deformation of interlayer rock mass will be investigated. As well, the optimal matching model of them will be constructed. With the analysis of stress and deformation characteristics at different media junctions, constitutive model and strength model of composite grouted layered rock under non-coordinated deformation conditions will be constructed. On the basis of coordination of stress and strain of different mediums in composite rock beam, the structural mechanics model of prestressed composite rock beam with expansive grouting of tunnel roof will be constructed. At the same time, the stress-deformation characteristics under the combination of external load, internal restraint stress and bond force will be analyzed. Finally, the grouting reinforcement mechanism of expansive grout in tunnel roof in steeply inclined layered rock with weak beddings will be revealed. The research results will provide the foundation for tunnel roof reinforcement of steeply inclined layered rock mass with weak beddings from the perspective of bedding reinforcement.

针对弱层理面急倾斜层状岩体巷道顶板易沿层理面发生“顺层滑移”破坏现象，开展对层理面两侧岩体形成挤压的“先挤后粘”膨胀型浆体注浆加固的膨胀约束应力和力学行为研究。采用岩石力学试验、数值模拟、相似模拟和理论分析等研究手段，分析膨胀约束应力与层间岩体法向约束变形之间的关系，并建立两者之间最优匹配模型；分析不同介质交界面处的应力和变形特征，构建非协调变形条件下的浆体-层间岩体复合体本构模型和强度模型；以组合岩梁不同介质之间的应力应变协调关系为基础，构建巷道顶板浆体-层间岩体预应力组合岩梁的结构力学模型，分析其在外部载荷-内部约束应力-粘结力复合条件下的应力变形特征，揭示出弱层理面急倾斜层状岩体巷道顶板膨胀注浆加固作用机理。研究成果将从层理面加固改良的角度为弱层理面急倾斜层状岩体巷道顶板加固提供基础。

针对急倾斜层状岩体巷道顶板支护困难问题，提出了膨胀型浆体“先挤后粘”注浆加固思路。项目主要研究内容为：1）膨胀型浆体注浆膨胀约束效应研究；2）浆体-层间岩体复合体力学行为研究；3）巷道顶板浆体-层间岩体预应力组合岩梁加固承载机制研究。.（1）采用岩石压力机、直剪仪、固结仪、扫描电镜、声发射监测仪等试验设备，针对不同配比的膨胀型浆体试样，系统研究了其膨胀性能和力学性能，并从微观层面揭示了其膨胀及强度变化机理。推导了不同约束条件下的膨胀型浆体膨胀应力函数和单轴压缩强度函数。基于此优选了最优膨胀型浆体配比，厘清了膨胀型浆体水化过程中膨胀挤压对岩体的约束效应。.（2）通过岩石力学理论分析，充分考虑膨胀应力对层间岩体的挤压和粘结作用，构建了基于Mohr—Coulomb理论的浆体-层间岩体复合体强度准则，并以此为基础构建了其压缩破坏模式预测模型，并通过室内试验检验了准则和模型的有效性。为充分分析膨胀型浆体的粘结性能，基于膨胀型浆体-层间岩体剪切试验结果，分析了复合体剪切强度与层理面厚度及法向应力的关系，定义了浆体-层间岩体的破坏模式。.（3）为研究巷道顶板浆体-层间岩体预应力组合岩梁加固承载机制问题，开展了急倾斜层状岩体巷道顶板膨胀型浆体注浆数值模拟和相似试验，通过监测数据分析了在外部载荷-内部约束应力-粘结力复合条件下的巷道顶板应力和变形特征，厘清了其协同承载机制，最终揭示出急倾斜层状岩体巷道顶板膨胀注浆加固作用机理，为急倾斜层状岩体巷道顶板支护提供新思路和技术支撑。